In the amavid conf filen, the @local_domains_maps line isn't the same that the one i got :In tuto :@local_domains_maps = ( [".$mydomain", "firstdomain.com", "new_domain.com"] );But in my conf file i doesn't have "$mydomain" : @local_domains_maps = ['sub.domain.com', 'domain.com'];However there is a line just before : chomp($mydomain = "sub.domain.com");

Because the amavisd conf file file say "#------------ Do not modify anything below this line -------------"

Re: How to enable DKIM for new domain ?

iRedMail configures Amavisd to sign all outgoing emails of all domains with the same DKIM key (the one created during iRedMail installation) by default, so you don't need a separate DKIM key for every mail domains.

If you created new DKIM key to replace the one created during iRedMail installation, it's fine, Amavisd will use it to sign other domains with default setting.